This invention relates to antireflection composite materials, and in particular, to an anti-reflective film.
There are many cases in which the visibility of information or an image through an optically transparent medium would be enhanced if the tendency of the surface to cause glare were reduced. Glare, or specular glare, is the undesirable reflection of light from a surface upon which light is incident. The reduction of reflection is desirable in numerous settings, including, for example, in vehicular windows, protective eyewear, computer monitor screens, television screens, and other display panels.
It is therefore desirable to provide an antireflection composite material for application to such surfaces that would reduce the amount of glare. Currently available antireflection composite materials on a surface typically include inorganic layers, for example, a metal or metal oxide layer, and a silica layer that includes SiOx, where x is an integer value typically equal to about 2. Additionally, a layer of indium tin oxide (ITO) may also be provided. Once the antireflection composite material is applied to the surface, an antireflection article is formed. However, both ITO and SiOx are difficult to sputter, and therefore, production costs for an antireflection article using ITO and/or SiOx are generally high.
In one aspect, a an article includes an antireflection composite material, a substrate, an inorganic layer deposited onto the substrate, and a polymer layer in contact with the inorganic layer to form an outer surface of the antireflection composite material. The inorganic layer has a thickness of from about 1 nm to about 10 nm. The polymer layer has a thickness of from about 70 nm to about 120 nm.
Embodiments may include one or more of the following features. For example, the inorganic layer may be formed from a metal. The metal may include nickel. The nickel may have a thickness of from about 2 nm to about 3.5 nm. The metal may include chromium. The inorganic layer may include titanium nitride.
The polymer layer may have a thickness of from about 100 nm to about 110 nm. The polymer layer may have a refractive index less than or equal to about 1.53 over the wavelength range of about 400 nm to about 700 nm.
The article may include a hard coat disposed between the substrate and the inorganic layer.
The inorganic layer may absorb a percentage of the incident light depending on an overall required transmission of the antireflection composite material. A thickness of the inorganic layer may depend on dispersion qualities of the inorganic layer.
A total thickness of the antireflection composite material may be about one-fourth of a wavelength that is a mean of the wavelengths in the visible spectrum. The total thickness of the antireflection composite material may equal a sum of the thickness of the inorganic layer and the thickness of the polymer layer.
The article may exhibit a photopic reflectance of less than about 0.5 percent over the wavelength range of about 400 nm to about 700 nm. The polymer layer may be formed by curing a curable composition in situ on the inorganic layer.
Aspects of the techniques and systems can include one or more of the following advantages. The single-inorganic layer structure provides antireflection performance substantially equal to that of previous antireflection composite materials that also include layers of other inorganic layers, while still providing a substantial reduction in production costs, since the thick silica layers and/or the other inorganic layers are eliminated.
The optically active outer polymer layer of carefully controlled refractive index above an inorganic layer reduces the overall cost of making and producing the antireflection composite material because the thickness of the inorganic layer can be greatly reduced. Moreover, an antireflection composite material that uses such an optically active outer polymer layer has good scratch and stain resistance, such as, for example, antifingerprinting resistance.
The antireflection composite material may be implemented on a CRT screens, including the newer flat panel screens that are produced by varying the thickness of the glass surface that serves as the optically transparent surface. Because of this varying thickness, tinted glass, which traditionally has served to reduce glare on CRT screens, cannot be used for the flat panel screens. The antireflection composite material may be implemented in organic light emitting diodes (LEDs) that have been used in hand-held devices.
The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims.